I don't have any problems seeing "Greater than" option when defining a custom Error on a service.
Select the service, -> Edit
Select Error Detection
Select Add Custom Error Rule
If I select a source thats defined to be a string, I don't get the "Greater Than' option. But if the source is defined to be Integer, the "Greater than" shows up.
But I"m not sure this is what you want. It sounds like you want to trigger on the quantity of transactions, not the value of a given transactions request parameter. Or does the Request Attribute contain the trigger value?
@Joseph M. H. yeah I was hopping to create a trigger if the quantity of transactions is greater than x (amount).
What I'm looking at is identifying Bot traffic - which I've done via request attribute. Now I'm trying to figure out the trend so I can establish a baseline to create a custom error event.